General fact: 28239 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 28239 is an uninteresting number.
Trivia: 28239 is an uninteresting number.
Historical date: April 24th is the day in 1932 that Benny Rothman leads the mass trespass of Kinder Scout, leading to substantial legal reforms in the United Kingdom.